Whales: A song
The great whales also have voices. Humpbacks (Megaptera novaeanglia), one of the baleen whales, congregate every spring in Hawaii to give birth to their young and to mate. Some of them also sing. Their song consists of a sequence of yelps, growls, high pitched squeals and long drawn out rumbles. And the whales declaim these songs hour after hour in extended stately recitals. They contain unchanging sequences of tones that have been called themes. Each theme may be repeated over and over again the number of times varies but the order of the themes in a song is always the same in any one season. Typically, a complete song lasts for about ten minutes, but some have been recorded that continue for half an hour and whales may sing, repeating their songs, virtually continuously for over twenty four hours. Each whale has its own characteristic song but it composes it from themes which it shares with the rest of the whale community in Hawaii. The whales stay in Hawaiian waters for several months, calving, mating and singing. Then, within a few days, the deep blue bays and straits off the Hawaiian islands are empty. The whales have gone. Humpbacks appear a few weeks later off Alaska. It is very likely that these are the Hawaiian animals but more studies will have to be made before we can be certain that they are. Next spring, they reappear in Hawaii and once more begin to sing. But this time they have new themes in their repertoire and have dropped many of the old ones.
We still do not know why whales sing although each individual whale can be identified by its song, which may mean that whales can do the same. Water transmits sound better than air so it may well be that sections of these songs, particularly those low vibrating notes, can be heard several kilometres away informing them of the whereabouts and activities of the whole whale community.